Enum AgentEvent 

pub enum AgentEvent {
    RunStarted {
        input: String,
        timestamp: Instant,
    },
    RunCompleted {
        output: String,
        duration: Duration,
    },
    RunFailed {
        error: String,
        duration: Duration,
    },
    ModelCallStarted {
        message_count: usize,
        tool_count: usize,
        timestamp: Instant,
    },
    ModelCallStreaming {
        delta: String,
        accumulated_length: usize,
    },
    ModelCallCompleted {
        response_content: String,
        tokens: Option<TokenUsage>,
        duration: Duration,
        stop_reason: Option<StopReason>,
    },
    ToolRequested {
        tool_use_id: String,
        name: String,
        input: Value,
    },
    ToolExecuting {
        tool_use_id: String,
        name: String,
    },
    ToolCompleted {
        tool_use_id: String,
        name: String,
        output: ToolResult,
        duration: Duration,
    },
    ToolFailed {
        tool_use_id: String,
        name: String,
        error: String,
        duration: Duration,
    },
    PermissionRequired {
        proposal_id: String,
        tool_name: String,
        params: Value,
        params_hash: String,
    },
    PermissionGranted {
        tool_use_id: String,
        tool_name: String,
        scope: Option<Scope>,
    },
    PermissionDenied {
        tool_use_id: String,
        tool_name: String,
        reason: String,
    },
}

Events emitted during agent execution

These events allow observers to track agent lifecycle, model calls, and tool executions in real-time.

Variants

RunStarted

Agent.run() started

Fields

input: String

User input message

timestamp: Instant

Timestamp

RunCompleted

Agent.run() completed

Fields

output: String

Final response to user

duration: Duration

Total execution duration

RunFailed

Agent.run() failed with error

Fields

error: String

Error message

duration: Duration

How long before failure

ModelCallStarted

Model API call started

Fields

message_count: usize

Messages being sent to model

tool_count: usize

Number of tools available to model

timestamp: Instant

Timestamp

ModelCallStreaming

Model streaming a token (only if streaming enabled)

Fields

delta: String

Incremental text delta

accumulated_length: usize

Accumulated length so far

ModelCallCompleted

Model API call completed

Fields

response_content: String

Response content

tokens: Option<TokenUsage>

Token usage statistics

duration: Duration

API call duration

stop_reason: Option<StopReason>

Stop reason from model

ToolRequested

Model requested a tool (fires exactly once per tool use)

Fields

tool_use_id: String

Unique ID for this tool use

name: String

Tool name

input: Value

Input parameters

ToolExecuting

Tool execution actually starting (after permission granted)

Fields

tool_use_id: String

Unique ID for this tool use

name: String

Tool name

ToolCompleted

Tool execution completed successfully

Fields

tool_use_id: String

Matching ID from ToolRequested

name: String

Tool name

output: ToolResult

Tool output

duration: Duration

Execution duration

ToolFailed

Tool execution failed

Fields

tool_use_id: String

Matching ID from ToolRequested

name: String

Tool name

error: String

Error message

duration: Duration

How long before failure

PermissionRequired

Tool execution requires permission

Fields

proposal_id: String

Unique ID for this permission request

tool_name: String

Tool name

params: Value

Tool input parameters

params_hash: String

Hash of parameters (for creating exact-match grants)

PermissionGranted

Permission granted (auto-approved or user-approved)

Fields

tool_use_id: String

Tool use ID

tool_name: String

Tool name

scope: Option<Scope>

The scope of the grant (None if one-time approval)

PermissionDenied

Permission denied

Fields

tool_use_id: String

Tool use ID

tool_name: String

Tool name

reason: String

Reason for denial

Trait Implementations

impl Clone for AgentEvent

fn clone(&self) -> AgentEvent

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for AgentEvent

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.